# coding: utf-8
import random   #生成随机数

def generat_unique_string():
    """
    :return: 返回唯一字符串
    """
    all_chars = "abcdefghijklmnopqrstuvwxyz0123456789"  #所有字符集
    #使用random.sample(all_chars,6) 从 all_chars 中提取6个不重复的和 "HC" 组成唯一字符
    unique_str = "HC" + "".join(random.sample(all_chars,6))
    return unique_str



